OK, particle effects work as fast, as monitor refresh rate works (and - as capable GPU is). And it sucks. In our upcoming game I have scenes built entirely around particle effects (rain, mist and so on) and my gpu is pushing more than 200+ frames on them. And it looks... just bad.
So ultimately - particles in VS are broken. Like, really, really broken.
Yes, you can visit the nvidia control panel and set "limit framerate to..." (if you have that option available - we discovered that it isn't accessible on all nvidia equipped systems). When it isn't there, you can always click "enable v-sync" - which seems like a solution. A long as you don't have a monitor with 144 Hz refresh rate...
We are looking for a person who can write a VS compatibile script that WILL LOCK particle effects at 60 fps (no matter what - that's a boundary we decided we cannot cross. Screw monitor refresh rates and so on).
If you can do that - it's a paid commission. Please contact us at firstname.lastname@example.org
One thing though - we will pay for your custom script, but since it's a crucial thing - WE WILL SHARE IT with the community. You can dictate a price, you can demand an "in-script" credit, but you cannot deny a redistribution.